divlb (designated ftsQ in E.coli and divlb in B.subtilus) is an essential gene involved in bacterial cell division. E.coli FtsQ has been identified as a DivIB homolog, being 18% identical and 44% similar (Harry et al., (1994) Gene 147 85-89). It has been shown in E.coli that FtsQ is required through out the whole process of septum formation during cell division. FtsQ is a simple cytoplasmic membrane protein with approx 25 amino acids in the cytoplasmic domain, 25 amino acids in the cytoplasmic membrane and approx. 225 amino acids in the periplasmic domain (Carson et al., 1991, J. Bacteriol. 173: 2187-2195). It is estimated that FtsQ is present at about 22 copies/cell (Carson et al., 1991, J. Bacteriol. 173: 2187-2195). DivBI of B.subtilus 168 is also essential for viability at 37.degree. C. and above and is required at all temperatures for the normal rate of cell division (Beall and Lutkenhaus, 1989, J.Bacteriol. 171: 6821-6834). The N-terminal domain of FtsQ which contains the cytoplasmic domain and most of the membrane spanning domain can be replaced with the portion of the N-terminal sequence of Mal G which includes the first membrane spanning region. This FtsQ-MalG fusion complemented a ftsQ temperature sensitive mutant, thus illustrating that the cytoplasmic and membrane spanning regions of FtsQ were dispensable (Dai et al., 1996, 178, 1328-1334), although a membrane spanning region of FtsQ was required to transport the protein to the periplasm. Descoteaux and Drapeau et al., 1987 (J. Bacteriol 169, 1938) concluded that FtsQ interacts with FtsZ, apart from this observation no other biochemical function of FtsQ is known.
Clearly, there is a need for factors that may be used to screen compounds for antibiotic activity and which may also be used to determine their roles in pathogenesis of infection, dysfunction and disease. There is a need, therefore, for identification and characterization of such factors which can play a role in preventing, ameliorating or correcting infections, dysfunctions or diseases.
The polypeptide of the present invention has amino acid sequence homology to a known DivIB proteins.